Answer:
Step-by-step explanation:
⇒ 
or
(Answer)
I believe there is no such AP...
Recursively, this sequence is supposed to be given by

so that




has to be an integer, which means there are 4 possible cases.
Case 1:
and
. But

Case 2:
and
. But

Case 3:
and
. But

Case 4:
and
. But
